The invention relates to a method for adjusting a window pane of a motor vehicle with anti-trap protection, more particularly for a window pane of a cabriolet and to a device for carrying out the method. It is directed to improving the detection of jamming incidents in so-called scissor gaps which adjoin a side edge of the window pane.
From DE 30 34 118 C2 a method is known for controlling a motor-driven window lifter with anti-trap protection which calculates on the basis of measured values of the drive train, dynamic characteristic values of the window pane, such as e.g. speed and acceleration, and compares successive data with each other. If within the monitoring range for the adjustment speed of the window pane a deceleration is determined which lies outside a permissible range then a trapped incident is assumed and the window pane is moved in reverse.
Using this detection principle, which is designed as an indirect anti-trap protection, quite good results have been obtained when sensing trapped parts of the body and objects which stand directly in the way of the adjusting direction, but this did not however relate to monitoring so-called scissor gaps, as occur in cabriolets, coupes and rear windows. Considerable shear stresses can appear in these side gaps before the described indirect anti-trap protection responds. Safely restricting the jamming forces can scarcely be reached in this way.
These problems can however be overcome by using a so-called direct detecting anti-trap protection such as for example by using an electric switch strip fitted along the edge of the pane or along the closing edge on the body side associated therewith. This system has the drawback however that the switch strips may have to be incorporated in the design of the vehicle and additional costs may be incurred. A corresponding system is described in DE 197 20 713 C1.
The object of the invention is to provide with simple means an anti-trap protection which ensures high functional reliability even for side scissor gaps.
According to this it is proposed that during the closing process in a first phase a window pane is moved substantially vertically (in the Z-direction) between an at least partially opened and a practically completely closed position whilst maintaining an acute-angled gap which widens out in the closing direction between the side edge of the pane and an associated closing edge of a further window pane or a bodywork part, and that then in the second phase of the closing movement the window pane undergoes a substantially horizontal displacement (in the X-direction) and/or a rotational movement about the transverse axis (Y-axis).
It is thereby possible to use a cost-effective passively detecting anti-trap protection with which it is possible to monitor as the window pane is closed first the substantially vertical movement phase and then the substantially horizontal movement phase. Shear stresses on any object which might possibly be trapped can practically no longer occur since as a result of the wedge-shaped gap which opens out in the closing direction the object is pushed in the direction of movement and is not restricted. The objects which engage in the so-called scissor gap are also subjected in the last phase of the closing movement only to the usual pressure strains as occur during the substantially vertical closing movement.
In order to reverse the path of movement according to the invention the adjusting mechanism has suitable guide slides or guide rails which control the path of the window pane through slide elements which are moved thereon. The slide elements are in active connection with a drive device of an adjusting mechanism and thus transfer the adjusting force to the window pane. Instead of guide slides or guide rails the phases of the vertical and horizontal adjusting movement of the window pane can also be controlled through a lever gearing. The acute angled gap between the side edge of the pane and an associated closing edge is kept constant during the vertically directed closing movement in order to ensure that during this phase nothing can be trapped. There is however also the possibility of slightly widening out the acute angled gap during the closing movement.
A preferred use of the invention stems from a simultaneous triggering of a closing command for two window panes which by their two side edges form a common closing area. The adjusting movements of the two window panes are controlled electronically and matched with each other so that between the side edges inside the region of the at least partially opened and the practically completely closed pane positions there always remains a non-constricting acute angled gap. The adjusting movement of the two window panes can thereby run synchronously so that the two window panes reach their closing positions simultaneously. In the last phase of the closing movement the window panes execute a substantially horizontal displacement (in the X-direction) and/or a rotational movement about the transverse axis (Y-axis).
Before the second and last phase of the closing movement of the window pane is executed in order to reach the fully closed window position, the upper edge of the pane should form with the associated outer contour of the body sealing area at the most such a narrow gap that it is not possible to insert parts of the body. Preferably the upper edge of the window pane is already located in part in the sealing area so that the upper edge is covered by the sealing profile.
Naturally the adjusting movement of the two window panes can also run asynchronously so that these reach their closing positions one after the other. A first window pane in the last phase of its closing movement thereby executes a substantially horizontal displacement (in the X-direction) and is operated at a higher adjusting speed than the second window pane which in the last phase of its closing movement executes a rotational movement about the transverse axis (Y-axis) whereby the first window pane reaches its closing position before the second window pane.
In the event that only the first window pane was opened and the second window pane remains closed after triggering a closing command at first the second window pane should be opened at least in part until a sufficiently large (defined) acute angled gap has arisen. After the opening of the second window pane or even during the opening process the first window pane can be moved into the closing position. The second window pane is then closed.
In order to safeguard that the window pane at the conclusion of the second phase of the closing movement has actually reached its fully closed position a second press into the substantially vertical direction (Y-direction) is recommended. To this end a control of the drive in said direction for a fraction of a second is generally sufficient.
The electronics unit which serves for the anti-trap protection function also controls the adjusting mechanics and movement sequences of the two window panes corresponding to a program filed in an electronic memory.